• Codon usage pattern and relative synonymous codon usage (RSCU) of mtDNA of Meloidogyne graminicola.Numbers on the Y-axis refer to the total number of codons (A) and the RSCU value (B). Codon families are provided on the X-axis. (nih.gov)
  • A codon is a series of three nucleotides (a triplet) that encodes a specific amino acid residue in a polypeptide chain or for the termination of translation (stop codons). (wikipedia.org)
  • There are 64 different codons (61 codons encoding for amino acids plus 3 stop codons) but only 20 different translated amino acids. (wikipedia.org)
  • The overabundance in the number of codons allows many amino acids to be encoded by more than one codon. (wikipedia.org)
  • The genetic codes of different organisms are often biased towards using one of the several codons that encode the same amino acid over the others-that is, a greater frequency of one will be found than expected by chance. (wikipedia.org)
  • Different factors have been proposed to be related to codon usage bias, including gene expression level (reflecting selection for optimizing translation process by tRNA abundance), %G+C composition (reflecting horizontal gene transfer or mutational bias), GC skew (reflecting strand-specific mutational bias), amino acid conservation, protein hydropathy, transcriptional selection, RNA stability, optimal growth temperature, hypersaline adaptation and dietary nitrogen. (wikipedia.org)
  • Although it has been shown that the rate of amino acid incorporation at more frequent codons occurs at a much higher rate than that of rare codons, the speed of translation has not been shown to be directly affected and therefore the bias towards more frequent codons may not be directly advantageous. (wikipedia.org)
  • Excluding the stop codons, a total of 3,281 amino acids are encoded by the M. graminicola mt genome. (nih.gov)
  • the codons encoding these amino acids are composed wholly of T and/or A, which may play an important role in the high A+T content of the entire mtDNA sequence. (nih.gov)
  • The selectionist model also explains why more frequent codons are recognized by more abundant tRNA molecules, as well as the correlation between preferred codons, tRNA levels and gene copy numbers. (wikipedia.org)
  • Optimal codons in fast-growing microorganisms, like Escherichia coli or Saccharomyces cerevisiae (baker's yeast), reflect the composition of their respective genomic tRNA pool. (wikipedia.org)
  • The nature of the codon usage-tRNA optimization has been fiercely debated. (wikipedia.org)
  • It is not clear whether codon usage drives tRNA evolution or vice versa. (wikipedia.org)
  • At least one mathematical model has been developed where both codon usage and tRNA expression co-evolve in feedback fashion (i.e., codons already present in high frequencies drive up the expression of their corresponding tRNAs, and tRNAs normally expressed at high levels drive up the frequency of their corresponding codons). (wikipedia.org)
  • In the NSD pathway, which targets mRNAs lacking termination codons, the ribosome is believed to translate through the 3' untranslated region and stall at the end of the poly(A) tail. (kegg.jp)
  • Several viral families (herpesvirus, lentivirus, papillomavirus, polyomavirus, adenovirus, and parvovirus) are known to encode structural proteins that display heavily skewed codon usage compared to the host cell. (wikipedia.org)
  • In other organisms that do not show high growing rates or that present small genomes, codon usage optimization is normally absent, and codon preferences are determined by the characteristic mutational biases seen in that particular genome. (wikipedia.org)
  • The suggestion has been made that these codon biases play a role in the temporal regulation of their late proteins. (wikipedia.org)
  • Organisms that show an intermediate level of codon usage optimization include Drosophila melanogaster (fruit fly), Caenorhabditis elegans (nematode worm), Strongylocentrotus purpuratus (sea urchin) or Arabidopsis thaliana (thale cress). (wikipedia.org)
  • Analysis of the base composition at each codon position of the 12 PCGs showed that the third codon position (90.3%) is higher in A+T content than the first (80.2%) and second (79.7%) codon positions (Table S1 in File S1). (nih.gov)
  • To force the cell to ignore the mutated stop codon and produce a complete dystrophin protein. (treat-nmd.org)
  • Screening a large number of drugs resulted in the identification of a drug that was also able to force cells to ignore mutated stop codons, without the toxic side effects. (treat-nmd.org)
  • Codons that are not present in the mitochondrial genome are indicated in red at the tops of the columns. (nih.gov)
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